A correlation between spin parameter and dark matter halo mass

Using a set of high-resolution dark matter only cosmological simulations we found a correlation between the dark matter halo mass M and its spin parameter lambda for objects forming at redshifts z > 10: the spin parameter decreases with increasing mass. However, halos forming at later times do not exhibit such a strong correlation, in agreement with the findings of previous studies. While we presented such a correlation in a previous study using the Bullock et al. (2001) spin parameter defintion we now defer to the classical definition showing that the results are independent of the definition.